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MG MGB Technical - Cool Air Intake

The inside of the engine compartment can get very warm or hot, especially on warm days. Yesterday on a hot rod show they equipped a car with a set of tubes and enclosures to bring air in directly from outside the car. Has anybody tried this with an MGB? With the standard filter system would hoses only run to the grill help? How about enclosing the air filters in boxes with a hose running to the grill? The heat inside the hood can get pretty nasty.
Bob Ekstrand

Bob; Cold air intake with a thermostatic preheater will in theory give you more power/gas mileage. The systems you describe,with an exhaust manifold preheater were omni-present when american cars had carbs.The Austin Healy LEMANS [mid 1950s] used an air box with flex hose to the grill with no preheater and it worked well,but who ever drove one in the winter?

I may be sufficient to slit the air passing through the radiator from the air going to the carbs.

On chrome bumper and early rubber bumper cars (with the mechanical fan radiator position) this can be done by enclosing the airfilters and taking a duct to a hole made in the radiator mounting panel.

However, many of the works prepared competition cars took the duct all the way to the grill. When looking at the front of the cars you can see a trumpet like intake mounted in the end of the chrome grill in place of some of the slats.
David Witham

on my 76 ruuber bumper gt. I cat a hole in the radiator mounting plate directly in front of the K&N filter and run two k&n Cold feed pipes to the filters throught there seems to have worked a treat, and very easy to do.

i have seen some B's with louves pressed into the bonnet do these do anything?
jr williamson

Jr, do you have any photos of that setup? I have K&N filters on my '77 B (converted to twin SUs).
David Steverson

On my 72B with original air filters, temporarily I used the black paperish flex vent hose material to run 1 hose from port on rear air filter and 1 hose from port on front air filter to a hand made metal box attached to the engine side of the radiator support frame (left side of car). The box allowed the two hoses to enter the box on one side and the forward part of the box enclosed the 2-3" hole that was already there.

I questioned, once I was done, whether that single hole in the radiator support frame was providing adequate air to carbs.

I never did get around to installing another hose in front of box inlet to get air "rammed" in from in front of the grill.

Another alternative would have been to run the two hoses down under to the front of the car and create a funnel air ram to force more cool fresh air to carbs.

In the end, I've removed the box and the hoses, defaulting back to original design.

I never could tell if there was any performance change, but I am a believer in pushing more fresh air to carbs - as I think these cars run too rich.

There's my 2cents.

R.W Anderson

Regarding louvres in the bonnet that JRW asked about, to let hot air out while moving, they need to be quite well to the front of the bonnet lid, say no more than half way back. The area at the back of the lid is a positive pressure area caused by the air dam that is the windscreen, that's why the heater intake is there - air is forced in by the motion of the car, so a louvre there won't be able to work.

If all you want to do is release hot air when the car is standing still in traffic and the fan is cooling the rad, then the position of the louvres is not so critical. Of course any louvre will let rain water in, so think about what's underneath before you make that irrevocable decision. In Britain on an ordinary 1800 MGB they shouldn't be necessary if the cooling system is in good order.
Mike Howlett

I have a Sebring front on my car and no oil cooler so I was thinking of ducting air from the middle two rectangular vents up to around the carbs.

The only problem is I think I might need to mount the number plate over those holes instead!
Simon Jansen

i'll try and get some pick posted for you david.
jr williamson

This thread was discussed between 01/06/2009 and 03/06/2009

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